Improvement in Heavy-Oil Reservoir Evaluation Using Nuclear Magnetic Resonance: Long Lake and Kinosis SAGD Projects, Alberta, Canada

摘要

The Lower Cretaceous McMurray Formation in Alberta is the primary bitumen-producing horizon in the Long Lake and Kinosis SAGD (steam-assisted gravity drainage) development projects. Conventional log analysis methods used to evaluate this heavy-oil reservoir employ a resistivity-based water-saturation (S-w) equation. These methods are challenged by the vertical and lateral variability in formation water resistivity (R-w), which is often unknown to the log analyst. In order to overcome this limitation, log-derived saturations are calibrated to Dean-Stark (DS) extraction results. However, not all wells are cored and this leaves a high level of uncertainty in the log-calculated 5,, in these wells. In addition, the core-measured porosities are often found higher than the corresponding wireline density porosity and the validity of core-measured saturation becomes questionable.